Abstract C75: Correlation of nephrectomy status and race with overall survival in patients with metastatic renal cell carcinoma

Introduction: In most settings median overall survival (OS) is longer for non-Hispanic whites when compared to non-Hispanic blacks with metastatic renal cell carcinoma (mRCC). However, the clinical outcome has been equally poor for both groups in patients who do not undergo nephrectomy. The primary objectives of this study were to explore the reasons why patients with mRCC do not undergo nephrectomy and to evaluate the impact of nephrectomy status and race on OS. Methods: After obtaining approval from the Institutional Review Board of Emory University and the Atlanta Research and Education Foundation, a retrospective chart review was conducted at the Atlanta VA Medical Center in conjunction with a longitudinal biomarker study of patients with mRCC. Patients who were treated with targeted therapy between 2005 and 2015 were eligible for inclusion. Nephrectomy status was assessed and the reasons for not undergoing nephrectomy were documented. Descriptive statistics were employed along with Kaplan-Meier survival analysis. Results: Forty four of the 46 patients from the biomarker study were included in the analysis of nephrectomy status (31 non-Hispanic whites and 13 non-Hispanic blacks; 2 Hispanics were not included). Of the non-Hispanic patients, 39 had unilateral disease and 5 had bilateral disease for a total of 49 primary tumors. Nephrectomy rates with respect to the number of primary tumors were 59% for non-Hispanic whites (n=20 of 34) and 53% for non-Hispanic blacks (n=8 of 15) for an overall rate of 57% (n=28 of 49). There was no significant difference in OS by race with a median of 29.5 months (2.42 years) for non-Hispanic blacks (95% C.I. 7.4 – 56.9 months) and 35.6 months (2.92 years) for non-Hispanic whites (95% C.I. 19.4 – 61.4 months) with a log-rank p-value of 0.88. Metastasis was present at the time of nephrectomy in 14 cases while the remaining 15 cases were the result of recurrence after nephrectomy with curative intent. Of the 21 primary tumors that were not resected in 19 non-Hispanic patients, metastases were present in most instances at the time decisions were made regarding nephrectomy (n=17 of 21; 81%). There were relative or absolute contraindications to nephrectomy for 12 of the primary tumors that were not resected (57%). These included unresectable tumors and patients with poor performance status, chronic kidney disease or other significant medical comorbidities. For the 9 remaining unresected primary tumors, no contraindications to surgery were identified, yet some patients declined of their own volition, others were not referred or re-referred to urology and some did not keep their follow up appointments with urology. Also, some surgeons did not recommend nephrectomy. As such, no predominant reason for absence of nephrectomy was identified for the group as a whole or by race. However, in the absence of nephrectomy, the median OS was only 15.5 months (1.27 years) with a 95% C.I. of 8.5 to 29.5 months, versus 45.2 months (3.71 years) for patients who had undergone nephrectomy with a 95% C.I. of 30.3 to 100.9 months and a log-rank p-value of 0.0002. Summary: No racial disparity in OS was observed in this retrospective study of a small number of patients at a single institution. However, absence of nephrectomy may be a significant confounding factor since it is a strong predictor of short survival irrespective of race. Larger studies are required. Of note, a nephrectomy was much less likely to have been performed in patients who had metastatic disease at the time of diagnosis. Though no predominant reason for absence of nephrectomy was found, key factors were identified such as unresectability, poor performance status, significant medical comorbidities, the failure to schedule or keep appointments with surgical staff, and patient choice to forego nephrectomy. Citation Format: Dale Kesley Robertson, Yuan Liu, Chao Zhang, Theresa Gillespie, John Petros, Muta Issa, Maria Ribeiro, Wayne B. Harris. Correlation of nephrectomy status and race with overall survival in patients with metastatic renal cell carcinoma. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr C75.